The Peltier effect is the creation of a heat difference by an electric voltage. The effect occurs when a current is passed through two dissimilar metals or semiconductors that are connected to one another at two junctions (Peltier junctions). The current drives a transfer of heat from one junction to the other, such that one of the junctions is cooled and the other is heated. Peltier coolers, also called thermo-electric coolers, are solid-state devices that utilize the Peltier effect for heating and/or cooling.
U.S. Pat. No. 6,746,474, PCT Publication WO 03/101354, and US Patent Application Publication 2004/0210286 to Saadat, which are incorporated herein by reference, describe techniques for cooling selected regions within a body. An implantable cooling system is used to cool regions of the brain, spinal cord, or fibrous nerve bodies, e.g., the vagus nerve, to about 30 degrees C., in order to diminish nerve impulses which control seizures or chronic pain. The system includes a heat exchanger attachable to a tubular body organ, such as the superior vena cava or the inferior vena cava, through which heat is dissipated. Also included is a heat pump such as a Peltier junction, which configured to be placed into contact with the region of tissue to be cooled. The heated portion of the Peltier junction is cooled by a liquid heat transfer medium which absorbs the heat form the junction and dissipates it into the tubular body organ.
US Patent Application Publication 2003/0028229 to Rothman, which is incorporated herein by reference, describes experiments in which a manually-activated Peltier device was placed in direct contact with a cortical slice. Seizures terminated within seconds of the onset of cooling, sometimes preceding a detectable drop in temperature measured near the top of the slice.
U.S. Pat. No. 6,629,990 to Putz et al., which is incorporated herein by reference, describes heat-removal techniques for treatment of movement disorder episodes, by intracranially suppressing movement disorder episodes upon the detection of physiological symptoms. A device includes a temperature-contact implanted at a targeted portion in the brain which is determined to be associated with such episodes and connection to an implanted heat-transfer operator, typically a Peltier cooler or a thermal-electric cooler. Heat transfer from the temperature-contact to the heat-transfer operator cools the targeted portion and suppresses the movement disorder episode. Such heat transfer is performed upon the sensing of symptoms which normally preface episodes.
US Patent Application Publication 2004/0167581 and PCT Publication WO 04/062481 to Mower, which are incorporated herein by reference, describe techniques for inhibiting the conduction of certain spurious electrical impulses in the heart by cooling one or more targeted portions of the heart. In an embodiment, a Peltier cooler is used to cool the targeted portions.
PCT Publication WO 04/032720 to Osorio et al., which is incorporated herein by reference, describes a multi-purpose electrode mechanism for detection and control of changes in brain state, including a shaft portion and extendible elements structured for insertion into target tissue of the brain of a subject, cooling means configured to operatively apply cooling therapy to the target tissue, stimulation means having at least one electrical contact structured to operatively apply electrical stimulation therapy to the target tissue, sensing means including at least one sensor monitoring a biological signal of the subject patient, and control means responsive to the sensing means. The control means is structured to, in response to signals from the sensing means that indicate the presence of a pre-determined physiological condition or occurrence of an undesirable state change, automatically cause the cooling means and/or the stimulation means to initiate or terminate the cooling therapy and/or the electrical stimulation therapy respectively and an energy source for powering the various components of the multi-purpose electrode mechanism.
U.S. Pat. No. 6,736,837 to Fox, which is incorporated herein by reference, describes methods for treating cancer and other diseases by modulating body temperature. Heat is directed to the hypothalamus of a warm-blooded animal to cool the animal, utilizing the physiological mechanisms that regulate body temperature to effect a compensatory cooling response, thereby lowering body temperature (hypothermia), and rendering other methods of lowering body temperature more effective. Heat may be withdrawn from the hypothalamus of an animal, cooling the hypothalamus, inducing a compensatory increase in body temperature (hyperthermia), and rendering other methods of raising body temperature more effective. Body temperature may be directly modulated by heat-exchange catheter positioned within a blood vessel of a patient.
U.S. Pat. No. 5,876,422 to van Groeningen, which is incorporated herein by reference, describes a cardiac pacing system for treating dangerous atrial arrhythmias. When an episode of such an arrhythmia is detected, the system operates to cool the A-V node so as to reversibly block conduction of the atrial excitations through to the ventricle, permitting uninterrupted asynchronous ventricular pacing during the episode. The system provides for an atrial lead having a Peltier element positioned toward its distal end, such that when the atrial lead distal end is affixed to the atrial heart wall, the cooling element is proximate to the A-V node. Upon detection of a dangerous atrial episode, the Peltier element is energized to cool the A-V node to point of effective block, and the pacemaker switches to asynchronous pacing. The atrial signals are continually monitored, and when the arrhythmia terminates on its own and a normal sinus rhythm is restored, the cooling is stopped, permitting the atrial excitations to be transferred through the A-V node and allowing a return of the pacemaker to a synchronous pacing mode.
U.S. Pat. No. 5,228,923 to Hed, which is incorporated herein by reference, describes a thermoelectric device, including a plurality of thermoelectric cells positioned circumferentially on an inner cylinder so that all the intracouple junctions are on the base of the inner cylinder and all the intercouple junctions are on an outer cylinder. When a voltage is applied in one direction, the inner surface of the inner cylinder cools off and heat is withdrawn from the core and rejected at the periphery (the outer surface of the outer cylinder). When the voltage is applied in the reverse direction, heat is pumped into the inner core.
U.S. Pat. No. 4,483,341 to Witteles, which is incorporated herein by reference, describes an implantable hypothermia instrument for the in-situ treatment of oncological disorders. The instrument includes a cylindrical casing terminating at a first end in a concave tumor-abutting portion of a thermoconductive material which is thermally adjacent the cold junction of a cascaded three-component solid state cooler and shaped to partially surround the target tissue in order to provide a convergent freezing effect. The cooler comprises a thermoelectric first cooling section, a thermomagnetic second cooling section, and an Ettingshausen third cooling section connected thermally in parallel to afford a stepped temperature reduction across a wide thermal gradient and to provide a temperature level, freezing rate and repetitive freeze/thaw cycles sufficient for tumor necrosis.
U.S. Pat. No. 6,839,594 to Cohen et al., which is incorporated herein by reference, describes apparatus for actuating a skeletal muscle of a patient, including a plurality of electrodes, which are adapted to be placed in a vicinity of a motor nerve that innervates the skeletal muscle. A control unit is adapted to drive a current between two or more of the plurality of electrodes, and to configure the current such that a first subset of axons in the nerve is excited by the current and such that a second subset of axons in the nerve is not excited by the current. In an embodiment, the apparatus includes a ring of elements typically comprising microelectrodes or electromagnets, arranged so as to partially or completely surround the motor nerve.